Formation of Shallow P-N Junction in Silicon Wafer by Solid-Phase Diffusion at Low-Temperatures.
Grant-in-Aid for Scientific Research (C)
|Allocation Type||Single-year Grants|
|Research Institution||Nippon Institute of Technology|
ISHIKAWA Yutaka Nippon Institute of Technology, Faculty of Engineering, Assistant Professor, 工学部, 助教授 (10168213)
|Project Period (FY)
1996 – 1998
Completed(Fiscal Year 1998)
|Budget Amount *help
¥2,200,000 (Direct Cost : ¥2,200,000)
Fiscal Year 1998 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1997 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1996 : ¥900,000 (Direct Cost : ¥900,000)
|Keywords||solid-phase diffusion / silicon / impurity / low-temperature process|
In the present work, it has been investigated to form pn junction in silicon wafer at low-temperatures. The pn junction can be formed at low-temperatures by using the enhanced diffusion of impurities (phosphorus and boron ) during heating of silicon with light irradiation. The important results are as follows.
1. The diffusion of impurities during heating of silicon with light irradiation from a halogen lamp or a xenon lamp is enhanced considerably. The diffusion coefficients of impurities in such conditions are 100-300 times larger than those during usual heating method by furnace.
2. It is possible to diffuse impurities into silicon at 540ﾟC by using the enhanced diffusion during heating with light irradiation.
3. The pn junction diode made by such method at low-temperatures indicates a good electrical characteristics.
4. After such enhanced diffusion, no defects are found in the silicon wafer. Therefore, it is concluded that the present method for doping of impurities at low-temperatures is useful to device fabrication.
5. The enhanced diffusion in (100)-oriented silicon wafer is larger than that in (111) wafer. While phosphorus and boron show a great enhanced diffusion, arsenic shows no enhanced diffusion.
6. The enhanced diffusion during light irradiation is due to generation of the excess self-interstitials in silicon wafer, which may be injected into silicon wafer from the interface between the diffusion source film and the silicon wafer during light irradiation.
7. The wavelength of light which is effective for the enhanced diffusion and the diffusion at low-temperatures is 0.6-1.0 mum.
Research Output (12results)